Presence of bubbles can retard the flow of a liquid as it progresses through a capillary tube of small diameter. The Jamin effect may be defined as that resistance to flow under pressure through a capillary tube which is encountered by liquid globules interspaced with large bubbles.
The actuality of this effect in the case of water is shown. It is concluded that the Jamin effect probably does not arise in the case of petroleum moving toward a producing well. That this effect retards underground water movement to any great extent appears doubtful.
One asphalt-base and one paraffine-base oil each exhibited greater adhesion for sand grains than did water under the laboratory conditions used. Hydraulic pressure produced more oil than did air pressure from similar artificial formations.
This effect or action is a phenomenon quite apart from frictional resistance and is due to difference of capillary pressure between two sides of the trapped globule. This effect can be described more easily by analyzing a trapped oil droplet or gas bubble in a preferentially water wet capillary tube.